SHANGHAI -- Jannik Sinner avenged his defeat to Ben Shelton in the fourth round of last year's Shanghai Masters with a 6-4, 7-6 (1) victory, spoiling the 22-year-old American's birthday Wednesday.
Like last year, the duel again featured some incredible shot-making and serving dominance but this time the 23-year old Italian prevailed to improve his record against Shelton to 4-1.
"Happy how I handled this situation, it's obviously a position where I have been last year, and where I am right now, it's different, so I'm happy to be in the position where I am," Sinner said.
Sinner's break in the ninth game was all that separated the duo in the opening set. Both players then dominated on their own serve through the second before the Italian sped away in the tiebreak and won the last seven points of the match to advance to his seventh ATP Masters 1000 quarterfinal of the year.
He will play fifth-ranked Daniil Medvedev, who earlier beat longtime rival Stefanos Tsitsipas 7-6 (3), 6-3, in a match where the Greek player launched into a minutes-long rant against the chair umpire Fergus Murphy over a time violation call and initially refused to continue playing.
In a similar incident the day before, Frances Tiafoe cursed repeatedly at a chair umpire after losing his third round match and later apologized.
Second-ranked Carlos Alcaraz, who won the China Open in a thriller against Sinner last week, made it 12 consecutive wins with a testing 6-4, 7-5 victory over French veteran Gael Monfils to advance to the quarterfinals.
Alcaraz needed all his shotmaking abilities to outmaneuver 38-year-old Monfils, with the 21-year-old Spaniard making 22 winners and taking a break in each set to clinch the match in 87 minutes.
The French Open and Wimbledon champion will play Tomas Machac in the quarterfinals.
Four-time champion Novak Djokovic continued his bid for a 100th career title with a 6-3, 6-2 win over 61st-ranked Roman Safiullin, but third-ranked Alexander Zverev was upset 6-4, 7-5 by David Goffin of Belgium.
Goffin, 33, will face seventh seed Taylor Fritz for a place in the semifinals. Fritz eased past Holger Rune of Denmark 6-1, 6-2 for his spot in the last eight.